“#1. Does preta’s have a āhāraja kāya or karaja kāya?”
– There are different kinds of pretas. Some are said to have an āhāraja kāya. But they have less-dense bodies like Devas.
“#2. To me, it seems like there’s a connection between pasada rupa’s and utuja kaya.”
– The time sequence is as follows. The kammaja kaya (with hadaya vatthu and pasada rupa) arise first at the patisandhi moment. It is created solely by kammic energy. That kammaja kaya starts generating citta and thus the cittaja kaya arises immediately afterward. Utuja rupa are produced by both the kammaja kaya and cittaja kaya and thus that comes next. That is the gandhabba with those three kāya.
– When that gandhabba gets into a womb, it starts making the āhāraja kāya or karaja kāya.